Enhancement of methyldopa metabolism with barbiturate

The spurious increase in serum catecholamine levels associated with methyldopa treatment can be reduced by the simultaneous administration of phenobarbitone. This accelerating effect of phenobarbitone on methyldopa metabolism has been demonstrated in relation to both adrenaline and noradrenaline, and investigations suggest that it is due to the effect of barbiturate on the activity of metabolizing enzymes.